Devices for insertion between a slipping wheel of a vehicle, such as an automobile, on a slippery road surface have been used before. For example, U.S. Pat. Nos. 2,443,319 and 3,786,989 describe various traction devices made from expanded metal sheets which are rectangular in shape.
One disadvantage of these devices was the difficulty of inserting the device between the spinning wheel of the vehicle and the road surface, especially when a rut had been developed in the road surface.
Another disadvantage of these prior art devices lies in the fact that if the wheel was spinning on a hard slippery road surface, such as ice, there was a tendency for the spinning wheel to engage the leading edge of the device and then whip it violently out of contact between the spinning wheel and the slippery road surface. This presented danger to anyone standing alongside of the vehicle.